Evaporative Emissions System: Testing and Inspection

Charcoal Canister:

CHARCOAL CANISTER VALVE TEST

With fuel canister removed, the following checks will determine if the valve located on top of canister is operating properly.

1. Using small length of vacuum hose connected to tank tube, blow into canister. Air should escape the air tube at bottom of canister.
2. Using same procedure above with hose connected to the purge tube, air should not pass through the canister valve.
3. Apply 20" of vacuum to vacuum signal line while blowing air into purge tube, air should come out of the "TB" tube.

If canister valve fails the above test, the canister should be replaced

Bi-Metal Vacuum Switching Valve:

EVAP THERMAL VACUUM VALVE (TVV) TEST

1. Remove vacuum hoses.
2. Connect a length of vacuum hose to valve with engine cold.
3. Blow into valve, air should pass through valve.
4. Start engine, run until normal operating temperature is obtained 60°C (140°F).
5. Blow into valve, air should not pass through valve.
6. If valve fails the above test, replace valve.

2-Way Check Valve:

TANK PRESSURE CONTROL (TPC) VALVE TEST


1. Remove 2-way check valve.
2. Blow hard into BLACK side of valve, air should pass through valve.
3. Blow lightly into orange side of valve, air should pass through. If 2-way check valve does not function as above replace valve.